Device and method for compressing a working medium

Abstract

The invention relates to a device and a method for compressing a working medium, comprising: compressing a drive medium in a compressor; moving a drive piston within a first cylinder by means of the compressed drive medium; moving a high-pressure piston, which compresses the working medium, within a second cylinder by means of the drive piston; and transferring heat from the compressed working medium to the compressed drive medium before the compressed drive medium enters the first cylinder of the drive piston.

The invention claimed is: 
     
       1. A device for compressing a working medium comprising:
 a compressor for compressing a gaseous drive medium; 
 a pressure translator with a drive piston which can be actuated by means of the gaseous drive medium within a first cylinder and with a high-pressure piston which compresses the working medium within a second cylinder, wherein the high-pressure piston has a smaller piston area than the drive piston; and 
 a heat exchanger between the compressor and the first cylinder of the pressure translator for transferring heat from the compressed working medium to the compressed gaseous drive medium. 
 
     
     
       2. The device according to  claim 1 , further comprising:
 a closed circuit for the gaseous drive medium with a first line from the compressor to the first cylinder and with a second line from the first cylinder to the compressor. 
 
     
     
       3. The device according to  claim 2 , wherein the compressor is designed to be fully hermetic, semi-hermetic or open. 
     
     
       4. The device according to  claim 3 , wherein the compressor and the closed circuit for the gaseous drive medium are adapted to guide the drive medium at pressure higher than ambient pressure in the circuit. 
     
     
       5. The device according to  claim 4 , further comprising
 a cooler for cooling the gaseous drive medium in the second line between the first cylinder of the pressure translator and the compressor. 
 
     
     
       6. The device according to  claim 5 , further comprising:
 a temperature measuring element in the second line, and 
 a control unit which on the one hand is connected to the temperature measuring element and on the other hand is connected to the cooler in order to control the cooler depending on the temperature of the gaseous drive medium in the second line. 
 
     
     
       7. The device according to  claim 5 , further comprising:
 a first buffer storage device between the compressor and the heat exchanger and/or a second buffer storage device between the cooler and the compressor. 
 
     
     
       8. A method for compressing a working medium comprising:
 compressing a gaseous drive medium in a compressor; 
 moving a drive piston by means of the compressed gaseous drive medium within a first cylinder; and 
 moving a high-pressure piston which compresses the working medium by means of the drive piston within a second cylinder, 
 wherein 
 heat is transferred from the compressed working medium to the compressed drive medium before entry of the compressed gaseous drive medium into the first cylinder of the drive piston, and 
 the high-pressure piston has a smaller piston area than the drive piston. 
 
     
     
       9. The method according to  claim 8 , wherein the working medium is gaseous. 
     
     
       10. The method according to  claim 9 , wherein the working medium is molecular hydrogen. 
     
     
       11. The method according to  claim 8 , further comprising:
 guiding the gaseous drive medium in a closed circuit from the compressor via the first cylinder back to the compressor. 
 
     
     
       12. The method according to  claim 11 , wherein the gaseous drive medium in the compressor is compressed from an input pressure to an output pressure, wherein the input pressure is higher than an ambient pressure. 
     
     
       13. The method according to  claim 12 , wherein the input pressure is between 0.5 bar and 50 bar. 
     
     
       14. The method according to  claim 13 , further comprising:
 cooling the gaseous drive medium emerging from the first cylinder by means of a cooler. 
 
     
     
       15. The method according to  claim 13 , wherein the input pressure is between 2 bar and 30 bar. 
     
     
       16. The method according to  claim 14 , wherein the gaseous drive medium is selected from air, nitrogen, CO 2 , argon or krypton or a mixture thereof.